Pyromorphite is mineral species composed of lead chlorophosphite. sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. It is part of a series with two other minerals; mimetite and vanadinite, the resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests. They were formerly confused under the names green lead ore and brown lead ore.